1. Field of the Invention
This invention relates to an electrochromic device. More specifically, this invention relates to an edge isolation-interconnect system for an electrochromic device, and a process and device for its manufacture. This application incorporates by reference the disclosure of co-pending patent application Ser. No. 08/119,749 filed Sep. 10, 1993 entitled MICRO-ELECTRONIC POWER SUPPLY FOR ELECTROCHROMIC EYEWEAR and which is subject to common ownership herewith.
2. Related Background Art
Problems with electrochromic (EC) devices that must be addressed include isolation and interconnect systems which are visible within the field of view of the device, uneven shade coloration, possible electrical shorting of the EC device, coloration of only a portion of the device, and a complicated, expensive process of applying the coating to the substrate.
Endo, et al., in U.S. Pat. No. 4,824,221, disclose an "Electrochromic Device" including multiple layers unsymmetrically coated between a two-layered, or "sandwich" substrate system. Due to the unsymmetrical coating, the edge isolation region of Endo is visible within the field of view of the substrate. Additionally, the uneven coating may result in uneven shade coloration, and coloration of only part of the substrate. In addition, the uneven coating of Endo is difficult to apply during mass production. Another drawback of Endo is that the double layer substrate system of Endo is expensive to manufacture, particularly in the field of prescription eyewear, windows and the like. Furthermore, the layer system described by Endo is used on a flat substrate, which does not include the process difficulties associated with coating an eyeglass lens. Thus, there is a need for an EC device which overcomes the drawbacks of the prior art.
Accordingly, objects of the current invention include providing an electrochromic device having coated layers on a flat or non-flat substrate, an edge isolation-interconnect system which is aesthetically pleasing, even shade colorization across the entire device, an edge isolation-interconnect system which inhibits electrical shorts, coloration of the entire field of view of the substrate, and a relatively straightforward, repeatable and cost-effective application process for coating layers on a single-layered, eccentric-shaped substrate such as an optical lens or large sheets of substrate which can be cut after the layers are coated thereon.